1. Field of the Invention
The present invention relates to an engine starting device.
2. Background Information
In conventional engine starting devices, a large current flows at the initial stage of starter motor energization (at the start of rotation of the crank shaft); therefore, the output voltage of the battery decreases so as to depend on the characteristics of the battery. This decrease in voltage has effects such as noise contamination and power supply cutoff on the electrical equipment installed in the vehicle. In contrast, the engine starting device disclosed in Japanese Laid-Open Patent Application No. 2004-257369 employs a configuration in which, in order to both suppress a decrease in battery voltage at the initial stage of starter motor energization and secure an output during cranking, a resistor and a bypass circuit are disposed in parallel between the battery and the starter motor, the bypass circuit is opened after engine startup has commenced until the engine exceeds the first upper dead center, and the bypass circuit is closed upon the engine exceeding the first upper dead center.